A large feed production enterprise in Shandong produces 500,000 tons of livestock and poultry feed annually. Its feed pellet drying process has problems of high energy consumption and low thermal efficiency. The traditional hot air furnace direct heating method results in a drying energy consumption of 120kWh per ton of feed pellets.
Technical pain points
1. Thermal efficiency is only 65%, and a large amount of heat energy is wasted with exhaust gas emissions
2. Drying temperature fluctuates greatly (±15℃), affecting feed quality
3. Coal-fired boiler exhaust gas is directly discharged, and environmental pressure is high
Solution
Use high-efficiency shell and tube heat exchanger system for heat recovery:
1. Waste gas waste heat recovery
Install a stainless steel heat exchanger at the tail of the drying tower to exchange 300℃ exhaust gas with fresh air, and increase the preheating intake temperature from 20℃ to 180℃.
2. Two-stage heat exchange system
First-stage heat exchange: exhaust gas-air heat exchange
Second-stage heat exchange: steam condensate waste heat recovery
Comprehensive thermal efficiency increased to 85%
3. Intelligent control
PLC automatically adjusts the opening of the heat exchanger valve to keep the drying temperature stable at 105±3℃
Customer evaluation
"This heat exchange system not only saves energy costs every year, but more importantly, it makes the moisture content of our feed products more uniform and extends the shelf life by 15 days."--Wang Gong, the company's production director, said.
This case proves that heat exchangers can achieve significant energy savings in feed drying, waste heat recovery is an effective way to reduce carbon emissions in the feed industry, and temperature stability directly affects the final quality of feed.
In the future, heat pump technology can be combined to further increase the system energy efficiency to more than 90%, providing a more environmentally friendly drying solution for the feed industry.